Plot

Shirakawa and Isobe enter the chamber where Number 35 is kept. Isobe warns of her awesome power, the reason why she is kept locked away. While that power level gives her an excellent chance of defeating Lucy, her instinct to kill any Humans around her is also more powerful. Isobe taunts that controlling Number 35 is next to impossible, and wonders if Shirakawa has plans to appeal to #35's emotions. The two are joined outside the chamber by a young pretty female scientist named Saito, who says that #35 thinks of her as a mother.

Saito tells them that while Number 35 should be physically capable of being taken out of her isolation chamber, it is also all she has ever known and that she may not be able to walk under her power. Isobe knows that Saito has worked with Number 35 since her birth, but has doubts over whether this will mean anything. Saito assures him that Number 35 looks upon and calls her Mother and that she is anxious to finally see the child in person, confident that Number 35 will know her immediately.

Isobe wonders if Saito can indeed control Number 35, and while Shirakawa is mostly convinced that she can, based on their relationship, she reveals another means of control they can exercise. Upon her birth, a series of bombs were implanted within her body, to explode via remote if she were beyond control. Shirakawa claims to a shocked Isobe that the move, though it once might have been considered extreme, has proven to be justified in the present. Despite these words, she recalls being shocked when informed of this by Chief Kakuzawa, who says that the bombs were Kurama's idea since as a responsible father, he didn't wish his daughter to hurt anyone. (This is the first piece of dialogue to confirm that Number 35 is, in fact, Kurama's daughter.) He also saw it as a leash on Kurama himself, and now a means to punish his betrayal and recoup the funds spent on keeping #35 alive.

Shirakawa hears the alarm indicating the withdrawal of the partitions in Number 35's chamber and witnesses the opening of the mammoth doors, leading to the almost anticlimactic call from Saito for Number 35, aka Mariko, to come out of the chamber and not be afraid. Naked and shivering, Mariko begins to feel her way out, barely able to walk and almost tripping over her feeding tube as she stumbles over. Isobe and Shirakawa take note of the guard in the control room who can detonate the bombs in Mariko at a moment's notice while Saito lovingly unwraps the gauze and bandages around the girl's face. Saito asks Mariko if she knows who she is, and Mariko speaks/asks 'Mama?'. While Saito takes comfort in this, Mariko lightly chuckles and says 'No You're Not.'

Saito feels torn in two—almost exploded—by Mariko's vectors, while Isobe and Shirakawa are overwhelmed by disgust at the sight. Shirakawa orders the bombs detonated, but the guard is knocked out by Saito's thrown upper torso, which crashes through the control room window. Isobe manages to set off the general alarm and urges a stunned Shirakawa to withdraw while Mariko draws ever closer, her power more than making up for her emaciated body. As her vectors reach out to kill Shirakawa, a bomb detonates within Mariko's right arm and destroys it, sending her into pain and incapacitating her. This rescue is revealed to be the last act of the dying Saito from within the control room. As guards burst in, Shirakawa urges that they surround her quickly, while the pain prevents the use of her powers. Shirakawa lays down the law to Mariko on the harsh lesson she has been taught: Obey or suffer even worse pain. Mariko screams and cries as she hears this.

At Maple House, Nana smiles as she delights in the first ice cream she has ever eaten, getting a bad case of brain freeze for her troubles, but still enjoying it. She and Mayu hear Kouta chastising Nyu for disassembling the grandfather clock that has always fascinated her. Seeing the girls behind him listening in, Kouta asks to speak to Nana.

While Mayu attempts to help Nyu reassemble the clock, she worries about Nana, who is inside the dining room, refusing to answer any questions Kouta or Yuka might have about her relationship with Nyu. Nana misinterprets some words from Kouta and thinks that she must leave when all Kouta meant was that she should do some chores. Outside, Mayu has the clock back upright, though she wonders if it will work, as it falls apart inside again, and the sound of Nana's tears draw her away. Yuka is holding Nana, who was afraid of being on her own again, but both Kouta and Yuka assure her that she can stay, and Yuka asks Mayu to show Nana how to do some simple things that are right now beyond her. Kouta even welcomes her to their home, sending Nana deeper into joyful tears. The two girls take a bath together, another luxury for Nana, who before only had a cold-water hose turned on her. She informs Mayu that she must still prepare to fight Nyu if she should become Lucy again, but hopes that will never happen, for she could be happy for a long time at Maple House.

Two policemen in Kamakura show Nana's picture to the crepe vendor she spoke to previously, and he confirms having seen her, a fact Isobe conveys to Shirakawa at the Diclonius Research Institute. He asks if Mariko is capable of capturing Nana, and Shirakawa responds that the bombs are keeping effective control of her. She then reveals that all matters concerning Number 35 are now in her hands and that she will inform Kurama of this. She learns to her shock that Kurama has quietly and quickly left the facility the previous night. Before she can ponder this development, she learns that Mariko's specialized transport is ready and awaits her arrival. Leaving, Shirakawa finds herself filled with doubts and concerns about what Kurama is doing.

Arakawa exhausted in her research nook, wonders at her perennial question of when her last shower was, as she goes through endless pages of photos on university students, looking for Kouta's picture. Pressured by the facility to come up with a face and a name, Arakawa is trapped, her pleas to hygiene ignored.

On the beach, Bando is clearing the area of garbage, frustrated by the cybernetic hand damaged in his battle with Nana. Kurama appears and offers to quietly fix the hand if Bando will kill a Diclonius he believes is coming there.

At Maple House, Nana is to take over giving Wanta his meals as her chore, although Mayu will have to show her how to do even that at first. Kouta is happy to hear this and tells Nana all they ask of her is that she contribute what she can the house. The implicit praise makes Nana blush, and as she looks away, she spies a picture of Kanae and asks who she is. Kouta tells them that his little sister passed away, and that, before she died, he said something harsh to her that he can now never take back, though he cannot remember what. Mayu and Nana take in this information, but Nyu rises and objects strongly to it, asking Kouta not to cry, even though he is not crying. A memory of the crying young Kouta assaults Nyu's mind and briefly triggers Nana's sense that Lucy has returned, but this passes, and the trio begins to look for Nyu, who ran off with a pair of scissors in hand. Outside, Nyu seems on the verge of cutting her throat with the scissors.

When Kouta finds her, Nyu has cut her hair into a rough copy of Kanae's haircut and claims to be Kanae, who forgives Kouta and asks him not to be sad. Mayu and Nana witness this, and Nana tells Mayu that Nyu is the kind person she said. Mayu has them leave the two alone. When Nyu keeps pleading that she's sorry, Kouta assumes she's still talking about the keepsake seashell she broke when she first arrived, but Nyu's memory keeps flashing to a tearful, blood-stained younger Kouta's face. He embraces her, saying that he feels like he's known her for a very long time. Yuka also sees this tender scene, and runs off, angry and jealous.

Mariko's transport copter makes its way over Kamakura, where Shirakawa finds she cannot reach Kurama. Mariko begins to ask a question. Below them, Kouta again finds Nyu working on the clock and allows this, figuring she can't break it any further than it is. He also notes that Yuka is late in returning home. Outside, Nana fills Wanta's food bowl, eventually filling it too much and amusing Mayu with mistaking Wanta's name for the type of 'creature' he is. Happy in the moment and saying it out loud, Nana's attention is drawn by her sensing of Mariko, and of Mariko sensing her as well. Aboard the transport, Mariko asks Shirakawa if it's alright to kill Nana because Nana is not Lucy, who she is to capture instead. Nana senses Mariko's power, viciousness and intent to kill her and begins to panic.

Arakawa continues to sort through the many thousands of photos of students at the university, still searching for the one who saw the horns on the head of the late Professor Kakuzawa. Purely by accident, she stumbles on Kouta's picture.

At Maple House, Nyu still works quietly on the clock while Mayu vainly attempts to calm the frantic Nana down. Kouta asks Mayu if she's seen Yuka, who went to fetch Soumen Noodles, a favorite food they thought Nana might like. Nana calms and excuses herself to go for a walk, a walk she promises to return from, but outside, she looks over Maple House as though for the last time and runs off.

Near the beachfront, Yuka stews over how Kouta looked at and held Nyu, fearing that she now has confirmation that he has always liked Nyu better. She breaks from her fog by seeing that the police have closed down Enoshima Park, and she sees two police officers she knows from elsewhere. The policemen speculate on why the facility has gone to all this trouble, and what the nature of their 'VIP' is.

Mariko disembarks from the transport, a wheelchair used to move her about since she still cannot walk under her legs' power, and with Shirakawa's stern warning of the bombs inside her and the control mechanism that needs to be reset every thirty minutes or they all explode. Isobe reports that the blockade is complete, and they can begin to search for Nana. Mariko shocks them by saying Nana is coming to them, which she sees as a chance for 'fun.'

At Maple House, Kouta questions Mayu about what she knows about Nana's departure, but Mayu doesn't know much beyond the unknown person that Nana said wanted to kill her. Mayu says that she so feared to bring trouble to the house, she left to keep it away. Kouta immediately gets ready to find Nana, declaring her a part of their family. He asks Mayu to stay behind and for her to instruct Yuka to do the same, but he cannot stop Nyu from following him. Yuka arrives back soon, asking Mayu where Kouta is.

On the beach, Bando and Kurama prepare amid tensions to do what they agreed to. Kouta and Nyu stop and watch a TV alert about a supposed police exercise in Enoshima.

To the stunned team supporting Mariko, Nana approaches, and Mariko again asks if it's okay to kill this Onee-Chan (Big Sister). Nana is taken aback by her opponent's age and size, determining to first use her arms as weapons to knock her out, then use her vectors. Before she can think further, she is surrounded by Mariko's vectors, far superior in number and strength to her own. In a heartbeat, she is stripped naked and her artificial limbs scattered, with Mariko chortling over how much fun she's having.

“

He himself had locked the past away. To bring it back, it took a formal dance, decorated in streams of blood, to an eerie music sung out by the last gasps of the dead. He watches as the belles of the ball move through their gruesome waltz, a sea of grudges, curses, sadness and love between them. On the next Elfen Lied, Episode Twelve : Quagmire.